{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-31507",
  "modified": "2026-10-07T17:22:01Z",
  "upstream": [
    "CVE-2026-31507"
  ],
  "published": "2026-04-22T13:57:42Z",
  "summary": "net/smc: fix double-free of smc_spd_priv when tee() duplicates splice pipe buffer",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/smc: fix double-free of smc_spd_priv when tee() duplicates splice pipe buffer\n\nsmc_rx_splice() allocates one smc_spd_priv per pipe_buffer and stores\nthe pointer in pipe_buffer.private.  The pipe_buf_operations for these\nbuffers used .get = generic_pipe_buf_get, which only increments the page\nreference count when tee(2) duplicates a pipe buffer.  The smc_spd_priv\npointer itself was not handled, so after tee() both the original and the\ncloned pipe_buffer share the same smc_spd_priv *.\n\nWhen both pipes are subsequently released, smc_rx_pipe_buf_release() is\ncalled twice against the same object:\n\n  1st call: kfree(priv)  sock_put(sk)  smc_rx_update_cons()  [correct]\n  2nd call: kfree(priv)  sock_put(sk)  smc_rx_update_cons()  [UAF]\n\nKASAN reports a slab-use-after-free in smc_rx_pipe_buf_release(), which\nthen escalates to a NULL-pointer dereference and kernel panic via\nsmc_rx_update_consumer() when it chases the freed priv->smc pointer:\n\n  BUG: KASAN: slab-use-after-free in smc_rx_pipe_buf_release+0x78/0x2a0\n  Read of size 8 at addr ffff888004a45740 by task smc_splice_tee_/74\n  Call Trace:\n   <TASK>\n   dump_stack_lvl+0x53/0x70\n   print_report+0xce/0x650\n   kasan_report+0xc6/0x100\n   smc_rx_pipe_buf_release+0x78/0x2a0\n   free_pipe_info+0xd4/0x130\n   pipe_release+0x142/0x160\n   __fput+0x1c6/0x490\n   __x64_sys_close+0x4f/0x90\n   do_syscall_64+0xa6/0x1a0\n   entry_SYSCALL_64_after_hwframe+0x77/0x7f\n   </TASK>\n\n  BUG: kernel NULL pointer dereference, address: 0000000000000020\n  RIP: 0010:smc_rx_update_consumer+0x8d/0x350\n  Call Trace:\n   <TASK>\n   smc_rx_pipe_buf_release+0x121/0x2a0\n   free_pipe_info+0xd4/0x130\n   pipe_release+0x142/0x160\n   __fput+0x1c6/0x490\n   __x64_sys_close+0x4f/0x90\n   do_syscall_64+0xa6/0x1a0\n   entry_SYSCALL_64_after_hwframe+0x77/0x7f\n   </TASK>\n  Kernel panic - not syncing: Fatal exception\n\nBeyond the memory-safety problem, duplicating an SMC splice buffer is\nsemantically questionable: smc_rx_update_cons() would advance the\nconsumer cursor twice for the same data, corrupting receive-window\naccounting.  A refcount on smc_spd_priv could fix the double-free, but\nthe cursor-accounting issue would still need to be addressed separately.\n\nThe .get callback is invoked by both tee(2) and splice_pipe_to_pipe()\nfor partial transfers; both will now return -EFAULT.  Users who need\nto duplicate SMC socket data must use a copy-based read path.",
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.47-1+rpt4"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-2712",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v6",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v8",
            "binary_version": "1:6.1.47-1+rpt4"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.47-1+rpt4": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.168",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-31507"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/7e8916f46c2f48607f907fd401590093753a6bc5"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/ae5575e660410c8d2c5d38fb28a0f37aea945676"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/98ba5cb274768146e25ffbfde47753652c1c20d3"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/81acbd345d405994875d419d43b319fee0b9ad62"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/7bcb974c771c863e8588cea0012ac204443a7126"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/54c87a730157868543ebdfa0ecb21b4590ed23a5"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/3cc76380fea749280c026f410af56a28aaac388a"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/24dd586bb4cbba1889a50abe74143817a095c1c9"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-05T13:16:28Z"
  }
}